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E. M. CHAFFEE.

Carriage-Spring. I No 61,712. 1 v Patented Feb. 5, I867.

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TO. ALL WHOM IT MAY CONCERN:

Be it known .thatI, EDWIN M. CHAFFEE, of Providence, in the county of Providence, and State of Rhode Island, have inventedn new Improvement in .Elliptic Springs; andI do hereby declare the following, when taken in connection with the accompanying drawings, and the letters of reference marked thereon, to be a full, clear,

and exact description of the same, and which said drawings constitute part of this specification, and represent, in-

Figures 1, 2 .;and 3, a side View of elliptic springs, of different construction, to which my improvement is applied; Q

My invention relates to an improvement in the common elliptic steel spring, and consists in the introduction of rubber or any of its allied gums between the plates or lifts of the springt'or the purpose of reducing and preventing the consequent results of friction between the plates.

It is well knon-n that in elliptic springs formed from plates that the-wear upon the severalplates occasioned A by the constant working of one upon another not only reduces the natural elasticity of the several layers, but.

wears away the metal so rapidly that this otherwise perfect spring is rcndcred impracticable for many places. By my invention these diiiiculties are entirely overcome; and to enable others skilled in-tlic-art to construct and use my improvement, I will proceed to describe the same, as illustrated in the accompanyingalrawings.

In fig. 1 the plates orlifts a b c (l are represented as formedft'rom thin metal. At the centre, between each of the lifts, I place a uietai or other plate, as denoted in black, which raises each lift slightly above the one below it then at or .near the points of each liit I place a piece of sheet rubber or similar elastic smbstancc,f,

fabricated or not, and at intervals on thelarger lifts, other pieces, '1', may be inserted. I find by experiment that the proper size of these pieces is about one-sixteenth of an inch thick and threc-eighths of an inch wide, and of a. length equal to the width of the plates. In fig. 2 a, spring of like construction, but solid plates, is shown, having the rubber introduced in like manner as in fig. 1. In fig. 3 I represent an old spring, into which the rubber is inserted in the following manner; raise the end of each lift slightly from theother, then insert the pieces of rubber in like manner as before described.

More or less pieces may be inserted, and of diil'erent size from this described;- but'as I have before stated, I find this arrangement to be the best for common carriage springs; larger or heavier springs would of course require proportionately increased dimensions of'the rubber. If required, the pieces of rubber may he cemented in their places, butthis I do not find necessary. The rubber thus inserted when the spring is compressed sus tains the plates one from the other, and the natural. elasticity of'the rubbtyields between the two surfaces, so

that the rubbing and consequent wear of one plate upon the other is wholly and entirely avoided. If after use it shall from any cause be necessary to replace the rubber, simply raise one plate from the other, remove the rubber, and insert a fresh piece. The wear, how-ever, upon the rubber is so slight that such change would be rendered almost unnecessary. If prci'erred, an indentation or recess maybe formed in the leaves of the spring to receive the rubber, so that the space between the leaves would be nearly closed. I Itherefore do not confine myself tothe precise manner of inserting the rubber, but having thus fully described my invention, what I claim as new and useful, and desire to secure by Letters Patent, is e The introduction of India rubber or similar elastic substance between the leaves or lifts of elastic springs,

substantially as and for the purposes specified, v

EDWIN M. 'GHAFFEE.

Witncsscs Hamillv MARTIN, CHARLES Stunts. 

